This invention relates to a transportation system comprising a plurality of guided vehicles, for instance of the type in which vehicles are moved on a conveyor, guided and partly supported by wheels rolling on a guiding rail, and provided with at least one braked wheel coming into contact with braking ramps transferring the vehicles from the conveyor to stations, and with launching ramps transferring the vehicles from the station to the conveyor.
As it is well known, a force applied to a vehicle in motion imparts to it an acceleration of a deceleration, depending upon the direction of the force compared to that of the motion.
The primary purpose of the invention is to provide a system able to control a force applied to the vehicle which is the reaction, parallel to the direction of the motion, of a longitudinal track component applied on the vehicle, through auxiliary means forming part of the vehicle, coming into contact with said track components at suitable places along the track, and providing a braking force which progressively cancels the relative velocity between the vehicle and the track component. If this component does not move, or moves in the direction of the motion more slowly than the vehicle, the braking force slows down the vehicle to the track component velocity, which may be zero; whereas if the track component moves faster than the vehicle, the same braking force with respect to said component accelerates the vehicle.
Therefore a transportation system related to the invention consists of vehicles comprising supporting and guiding means and an automatic brake-clutch system acting upon the motion of the vehicles relative to longitudinal track components.
We still remain in the field of the invention if the vehicle supporting and guiding means varied, being skis or air-cushions for instance instead of wheels; or if the means of propulsion are varied, the vehicle being for instance pulled by a cable or provided with a motor instead of being moved by a conveyor; on condition that means are provided for cancelling the propulsive effect on the vehicle when the braking means act upon it.
In the same fashion, we still remain in the field of the invention when changing the auxiliary means aboard the vehicle, where the braking force is applied : these means may be brake shoes directly contacting a longitudinal track component, or at least one auxiliary wheel braked on a drum, or on a disk, or any system providing a braking force proportional to the normal force on the brake. In accordance with the chosen auxiliary brake-clutch means, the track component able to come into contact thereto may be a vertical strip or a fixed ramp or a ramp fitted with a slow or a fast belt.
Indeed the purpose of the invention describing the automatic brake-clutch device is to provide a novel improvement of the French certificate of utility No. 71.27850 of July 2, 1971, particularly to provide a braking force that is proportional to the weight of the vehicle whatever the load and its distribution within the vehicle.
In many applications, such as automatic handling, transportation systems, it is essential to obtain a force that is proportional to the moving mass in order to change the speed in constant space and time with a very small dispersion. Using control means might result in insufficient precision, unless the moving mass is measured in some manner and this measure used to generate a signal proportional to it. This amounts to weighing the vehicle at any time. However, weighing a load which may consist of passengers that are anywhere and in any number in a vehicle for instance requires the use of some techniques which are described below.